title: Synthetic peptides reactive with anti-human milk fat globule membrane monoclonal antibodies.
abstract: Mammary mucins are increased in amounts in breast cancer patient sera, and most anti-breast cancer antibodies react with such mucins. One such mucin is found in human milk fat globule membrane and consists predominantly of O-linked sugars and a protein core. Partial complementary DNA clones for the protein core have recently been obtained. The nucleotide sequence is of interest as it contains a 60-base pair repeat, giving rise to a repeated 20-amino acid sequence (PDTRPAPGSTAPPAHGVTSA). Peptides with various lengths were synthesized using this sequence and the adjacent 4 amino acids (PDTR). Three anti-human milk fat globule membrane antibodies produced in our laboratory (BC1, BC2, and BC3) were tested to determine their reactivity with these synthetic peptides. Using three different assays (direct enzyme-linked immunosorbent assay test on peptides, direct enzyme-linked immunosorbent assay test on bovine serum albumin-conjugated peptides, and an inhibition test with the peptides in liquid, rather than solid phase), it was shown that APDTR was the minimum amino acid sequence required to form a reactive epitope with all 3 antibodies, although individual differences in the reactivities of the antibodies were noted. The addition of alanine (A) converted a nonreactive PDTR peptide to a reactive one, and the deletion of arginine (R) did the reverse; thus APDTR is the smallest peptide which reacts with these anti-human milk fat globule membrane antibodies.
authors.affiliation: Department of Pathology, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: P X
authors.initials: PX
authors.lastname: Xing
authors.forename: K
authors.initials: K
authors.lastname: Reynolds
authors.forename: J J
authors.initials: JJ
authors.lastname: Tjandra
authors.forename: X L
authors.initials: XL
authors.lastname: Tang
authors.forename: I F
authors.initials: IF
authors.lastname: McKenzie
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000937:Antigen-Antibody Reactions; D000951:Antigens, Neoplasm / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000276:immunology*; D008969:Molecular Sequence Data; D018396:Mucin-1; D009842:Oligopeptides / Q000138:chemical synthesis / Q000276:immunology; D010455:Peptides / Q000138:chemical synthesis* / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D008562:Membrane Glycoproteins; D018396:Mucin-1; D009842:Oligopeptides; D010455:Peptides